This invention relates to brakes for bicycles, and more particularly to a device by which a brake shoe having a brake block engageable with and disengageable from the rim of a wheel is supported on a brake arch by threaded fastening means.
With side-pull or center-pull caliper brakes for bicycles, each brake shoe is usually mounted in place by inserting a shoe stem integral with the shoe into a support bore in a brake arch and fastening a nut to the projecting end to the shoe stem.
Further with cantilever brakes, it is generally practiced to braze a base to a specified portion such as the front fork blade of the bicycle, pivotably mount a brake arch on the base in a cantilever fashion, fasten an eyebolt to the arch by a threaded member and insert the brake shoe stem into the eyebolt. In the case of the cantilever type, the base is frequently brazed to its support as deviated from the desired position, with the result that when the cantilever brake is mounted on the base, the brake shoe will not be properly positioned with respect to the rim surface, or difficulty will be experienced in effecting a brake action by causing the brake block to contact the rim surface progressively from its front end in the direction of advance of the rim.
Further with side-pull or center-pull brakes, it is extremely difficult to position the brake block at an accurate angle with the wheel rim surface, so that reduced braking efficiency is encountered. If the brake block is so positioned that the entire surface of the block will come into sliding contact with the rim surface, the brake operates suddenly with high impact, posing safety problems.
Thus with the conventional brakes for bicycles, the pair of brake blocks is mounted on the opposite sides of the wheel rim surface for engagement with and disengagement from the rim surface, in such manner that the brake shoe, crimped to hold each of the brake blocks is fastened to the brake arch by screw means and is not shiftable for the adjustment of its position. Consequently it is difficult to permit the brake blocks to intimately contact the rim surface with accuracy.